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Kaufmann P, Zweier L, Baca A, Kainz H. Muscle synergies are shared across fundamental subtasks in complex movements of skateboarding. Sci Rep 2024; 14:12860. [PMID: 38834832 DOI: 10.1038/s41598-024-63640-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 05/30/2024] [Indexed: 06/06/2024] Open
Abstract
A common theory of motor control posits that movement is controlled by muscle synergies. However, the behavior of these synergies during highly complex movements remains largely unexplored. Skateboarding is a hardly researched sport that requires rapid motor control to perform tricks. The objectives of this study were to investigate three key areas: (i) whether motor complexity differs between skateboard tricks, (ii) the inter-participant variability in synergies, and (iii) whether synergies are shared between different tricks. Electromyography data from eight muscles per leg were collected from seven experienced skateboarders performing three different tricks (Ollie, Kickflip, 360°-flip). Synergies were extracted using non-negative matrix factorization. The number of synergies (NoS) was determined using two criteria based on the total variance accounted for (tVAF > 90% and adding an additional synergy does not increase tVAF > 1%). In summary: (i) NoS and tVAF did not significantly differ between tricks, indicating similar motor complexity. (ii) High inter-participant variability exists across participants, potentially caused by the low number of constraints given to perform the tricks. (iii) Shared synergies were observed in every comparison of two tricks. Furthermore, each participant exhibited at least one synergy vector, which corresponds to the fundamental 'jumping' task, that was shared through all three tricks.
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Affiliation(s)
- Paul Kaufmann
- Department of Biomechanics, Kinesiology and Computer Science in Sport, Centre for Sport Science and University Sports, University of Vienna, Auf der Schmelz 6a (USZ II), 1150, Vienna, Austria
- Neuromechanics Research Group, Centre for Sport Science and University Sports, University of Vienna, Vienna, Austria
| | - Lorenz Zweier
- Department of Biomechanics, Kinesiology and Computer Science in Sport, Centre for Sport Science and University Sports, University of Vienna, Auf der Schmelz 6a (USZ II), 1150, Vienna, Austria
- Neuromechanics Research Group, Centre for Sport Science and University Sports, University of Vienna, Vienna, Austria
| | - Arnold Baca
- Department of Biomechanics, Kinesiology and Computer Science in Sport, Centre for Sport Science and University Sports, University of Vienna, Auf der Schmelz 6a (USZ II), 1150, Vienna, Austria
| | - Hans Kainz
- Department of Biomechanics, Kinesiology and Computer Science in Sport, Centre for Sport Science and University Sports, University of Vienna, Auf der Schmelz 6a (USZ II), 1150, Vienna, Austria.
- Neuromechanics Research Group, Centre for Sport Science and University Sports, University of Vienna, Vienna, Austria.
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Ahn J, Simpkins C, Shin S, Yang F. Shoe sole impedes leg muscle activation and impairs dynamic balance responding to a standing-slip. J Biomech 2024; 169:112138. [PMID: 38728788 DOI: 10.1016/j.jbiomech.2024.112138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 04/28/2024] [Accepted: 05/05/2024] [Indexed: 05/12/2024]
Abstract
The shoe sole is identified as a fall risk factor since it may impede the afferent information about the outside world collected by the plantar sensory units. However, no study has directly quantified how the shoe sole compromises body balance and increases fall risk. This study aimed to inspect how the sole affects human balance after an unexpected standing-slip. It was hypothesized that individuals wearing the sole, relative to their barefoot counterparts, would exhibit 1) more impaired stability and 2) disrupted lower limb muscle activation following a standing-slip. Twenty young adults were evenly randomized into two groups: soled and barefoot. The soled group wore a pair of customized 10-mm thick soles, while the other group was bare-footed. Full-body kinematics and leg muscle electromyography (EMG) were collected during a standardized and unexpected standing-slip. The EMG electrodes were placed on the tibialis anterior, gastrocnemius, rectus femoris, and biceps femoris bilaterally. Dynamic stability, spatiotemporal gait parameters, and the EMG latency of the leg muscles were compared between groups. The sole impeded the initiation of the recovery step possibly because it interfered with the accurate detection of the external perturbation and subsequently activated the leg muscles later in the soled group than in the barefoot group. As a result, individuals in the soled group experienced a longer slip distance and were more unstable than the barefoot group at the recovery foot liftoff. The findings of this study could augment our understanding of how the shoe sole impairs body balance and increases the fall risk.
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Affiliation(s)
- Jiyun Ahn
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA, USA
| | - Caroline Simpkins
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA, USA
| | - Sangwon Shin
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA, USA
| | - Feng Yang
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA, USA.
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Brüll L, Santuz A, Mersmann F, Bohm S, Schwenk M, Arampatzis A. Spatiotemporal modulation of a common set of muscle synergies during unpredictable and predictable gait perturbations in older adults. J Exp Biol 2024; 227:jeb247271. [PMID: 38506185 PMCID: PMC11058090 DOI: 10.1242/jeb.247271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 03/14/2024] [Indexed: 03/21/2024]
Abstract
Muscle synergies as functional low-dimensional building blocks of the neuromotor system regulate the activation patterns of muscle groups in a modular structure during locomotion. The purpose of the current study was to explore how older adults organize locomotor muscle synergies to counteract unpredictable and predictable gait perturbations during the perturbed steps and the recovery steps. Sixty-three healthy older adults (71.2±5.2 years) participated in the study. Mediolateral and anteroposterior unpredictable and predictable perturbations during walking were introduced using a treadmill. Muscle synergies were extracted from the electromyographic activity of 13 lower limb muscles using Gaussian non-negative matrix factorization. The four basic synergies responsible for unperturbed walking (weight acceptance, propulsion, early swing and late swing) were preserved in all applied gait perturbations, yet their temporal recruitment and muscle contribution in each synergy were modified (P<0.05). These modifications were observed for up to four recovery steps and were more pronounced (P<0.05) following unpredictable perturbations. The recruitment of the four basic walking synergies in the perturbed and recovery gait cycles indicates a robust neuromotor control of locomotion by using activation patterns of a few and well-known muscle synergies with specific adjustments within the synergies. The selection of pre-existing muscle synergies while adjusting the time of their recruitment during challenging locomotor conditions may improve the effectiveness to deal with perturbations and promote the transfer of adaptation between different kinds of perturbations.
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Affiliation(s)
- Leon Brüll
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Network Aging Research, Heidelberg University, 69115 Heidelberg, Germany
| | - Alessandro Santuz
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Falk Mersmann
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Sebastian Bohm
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Michael Schwenk
- Network Aging Research, Heidelberg University, 69115 Heidelberg, Germany
- Institute of Sports and Sports Sciences, Heidelberg University, 69120 Heidelberg, Germany
- Department of Sport Science, Human Performance Research Center, University of Konstanz, 78464 Konstanz, Germany
| | - Adamantios Arampatzis
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Berlin School of Movement Science, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
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Saito H, Yokoyama H, Sasaki A, Nakazawa K. Direction-Specific Changes in Trunk Muscle Synergies in Individuals With Extension-Related Low Back Pain. Cureus 2024; 16:e54649. [PMID: 38523944 PMCID: PMC10959767 DOI: 10.7759/cureus.54649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2024] [Indexed: 03/26/2024] Open
Abstract
Background Identifying altered trunk control is critical for treating extension-related low back pain (ERLBP), a common subgroup classified by clinical manifestations. The changed coordination of trunk muscles within this group during particular trunk tasks is still not clearly understood. Objectives The objective of this study is to investigate trunk muscle coordination during 11 trunk movement and stability tasks in individuals with ERLBP compared to non-low back pain (LBP) participants. Methods Thirteen individuals with ERLBP and non-LBP performed 11 trunk movement and stability tasks. We recorded the electromyographic activities of six back and abdominal muscles bilaterally. Trunk muscle coordination was assessed using the non-negative matrix factorization (NMF) method to identify trunk muscle synergies. Results The number of synergies in the ERLBP group during the cross-extension and backward bend tasks was significantly higher than in the non-LBP group (p<0.05). The cluster analysis identified the two trunk synergies for each task with strikingly similar muscle activation patterns between groups. In contrast, the ERLBP group exhibited additional trunk muscle synergies that were not identified in the non-LBP group. The number of synergies in the other tasks did not differ between groups (p>0.05). Conclusion Individuals with ERLBP presented directionally specific alterations in trunk muscle synergies that were considered as increased coactivations of multiple trunk muscles. These altered patterns may contribute to the excessive stabilization of and the high frequency of hyperextension in the spine associated with the development and persistence of ERLBP.
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Affiliation(s)
- Hiroki Saito
- Department of Physical Therapy, Tokyo University of Technology, Tokyo, JPN
| | - Hikaru Yokoyama
- Division of Advanced Health Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Tokyo, JPN
| | - Atsushi Sasaki
- Department of Physical Medicine and Rehabilitation, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, USA
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, JPN
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Hinnekens E, Berret B, Morard E, Do MC, Barbu-Roth M, Teulier C. Optimization of modularity during development to simplify walking control across multiple steps. Front Neural Circuits 2024; 17:1340298. [PMID: 38343616 PMCID: PMC10853381 DOI: 10.3389/fncir.2023.1340298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 12/14/2023] [Indexed: 02/15/2024] Open
Abstract
Introduction Walking in adults relies on a small number of modules, reducing the number of degrees of freedom that needs to be regulated by the central nervous system (CNS). While walking in toddlers seems to also involve a small number of modules when considering averaged or single-step data, toddlers produce a high amount of variability across strides, and the extent to which this variability interacts with modularity remains unclear. Methods Electromyographic activity from 10 bilateral lower limb muscles was recorded in both adults (n = 12) and toddlers (n = 12) over 8 gait cycles. Toddlers were recorded while walking independently and while being supported by an adult. This condition was implemented to assess if motor variability persisted with reduced balance constraints, suggesting a potential central origin rather than reliance on peripheral regulations. We used non-negative matrix factorization to model the underlying modular command with the Space-by-Time Decomposition method, with or without averaging data, and compared the modular organization of toddlers and adults during multiple walking strides. Results Toddlers were more variable in both conditions (i.e. independent walking and supported by an adult) and required significantly more modules to account for their greater stride-by-stride variability. Activations of these modules varied more across strides and were less parsimonious compared to adults, even with diminished balance constraints. Discussion The findings suggest that modular control of locomotion evolves between toddlerhood and adulthood as the organism develops and practices. Adults seem to be able to generate several strides of walking with less modules than toddlers. The persistence of variability in toddlers when balance constraints were lowered suggests a link with the ability to explore rather than with corrective mechanisms. In conclusion, the capacity of new walkers to flexibly activate their motor command suggests a broader range of possible actions, though distinguishing between modular and non-modular inputs remains challenging.
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Affiliation(s)
- Elodie Hinnekens
- Université Paris-Saclay, CIAMS, Orsay, France
- Université Paris-Saclay, CIAMS, Orléans, France
| | - Bastien Berret
- Université Paris-Saclay, CIAMS, Orsay, France
- Université Paris-Saclay, CIAMS, Orléans, France
| | - Estelle Morard
- Université Paris-Saclay, CIAMS, Orsay, France
- Université Paris-Saclay, CIAMS, Orléans, France
| | - Manh-Cuong Do
- Université Paris-Saclay, CIAMS, Orsay, France
- Université Paris-Saclay, CIAMS, Orléans, France
| | - Marianne Barbu-Roth
- Université Paris Cité, CNRS, Integrative Neuroscience and Cognition Center, Paris, France
| | - Caroline Teulier
- Université Paris-Saclay, CIAMS, Orsay, France
- Université Paris-Saclay, CIAMS, Orléans, France
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Saito H, Yokoyama H, Sasaki A, Nakazawa K. Muscle synergy patterns as altered coordination strategies in individuals with chronic low back pain: a cross-sectional study. J Neuroeng Rehabil 2023; 20:69. [PMID: 37259142 DOI: 10.1186/s12984-023-01190-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 05/10/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND Chronic low back pain (CLBP) is a highly prevalent disease with poorly understood underlying mechanisms. In particular, altered trunk muscle coordination in response to specific trunk tasks remains largely unknown. METHODS We investigated the muscle synergies during 11 trunk movement and stability tasks in 15 healthy individuals (8 females and 7 males, aged 21. 3 (20.1-22.8) ± 0.6 years) and in 15 CLBP participants (8 females and 7 males, aged 20. 9 (20.2-22.6) ± 0.7 years) by recording the surface electromyographic activities of 12 back and abdominal muscles (six muscles unilaterally). Non-negative matrix factorization was performed to extract the muscle synergies. RESULTS We found six trunk muscle synergies and temporal patterns in both groups. The high similarity of the trunk synergies and temporal patterns in the groups suggests that both groups share the common feature of the trunk coordination strategy. We also found that trunk synergies related to the lumbar erector spinae showed lower variability in the CLBP group. This may reflect the impaired back muscles that reshape the trunk synergies in the fixed structure of CLBP. Furthermore, the higher variability of trunk synergies in the other muscle regions such as in the latissimus dorsi and oblique externus, which were activated in trunk stability tasks in the CLBP group, represented more individual motor strategies when the trunk tasks were highly demanding. CONCLUSION Our work provides the first demonstration that individual modular organization is fine-tuned while preserving the overall structures of trunk synergies and temporal patterns in the presence of persistent CLBP.
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Affiliation(s)
- Hiroki Saito
- Graduate School of Arts and Sciences, Department of Life Sciences, The University of Tokyo, Tokyo, Japan
- Department of Physical Therapy, Tokyo University of Technology, Tokyo, Japan
| | - Hikaru Yokoyama
- Institute of Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan.
| | - Atsushi Sasaki
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, Osaka, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Kimitaka Nakazawa
- Graduate School of Arts and Sciences, Department of Life Sciences, The University of Tokyo, Tokyo, Japan
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Spomer AM, Yan RZ, Schwartz MH, Steele KM. Motor control complexity can be dynamically simplified during gait pattern exploration using motor control-based biofeedback. J Neurophysiol 2023; 129:984-998. [PMID: 37017327 PMCID: PMC10125030 DOI: 10.1152/jn.00323.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 04/06/2023] Open
Abstract
Understanding how the central nervous system coordinates diverse motor outputs has been a topic of extensive investigation. Although it is generally accepted that a small set of synergies underlies many common activities, such as walking, whether synergies are equally robust across a broader array of gait patterns or can be flexibly modified remains unclear. Here, we evaluated the extent to which synergies changed as nondisabled adults (n = 14) explored gait patterns using custom biofeedback. Secondarily, we used Bayesian additive regression trees to identify factors that were associated with synergy modulation. Participants explored 41.1 ± 8.0 gait patterns using biofeedback, during which synergy recruitment changed depending on the type and magnitude of gait pattern modification. Specifically, a consistent set of synergies was recruited to accommodate small deviations from baseline, but additional synergies emerged for larger gait changes. Synergy complexity was similarly modulated; complexity decreased for 82.6% of the attempted gait patterns, but distal gait mechanics were strongly associated with these changes. In particular, greater ankle dorsiflexion moments and knee flexion through stance, as well as greater knee extension moments at initial contact, corresponded to a reduction in synergy complexity. Taken together, these results suggest that the central nervous system preferentially adopts a low-dimensional, largely invariant control strategy but can modify that strategy to produce diverse gait patterns. Beyond improving understanding of how synergies are recruited during gait, study outcomes may also help identify parameters that can be targeted with interventions to alter synergies and improve motor control after neurological injury.NEW & NOTEWORTHY We used a motor control-based biofeedback system and machine learning to characterize the extent to which nondisabled adults can modulate synergies during gait pattern exploration. Results revealed that a small library of synergies underlies an array of gait patterns but that recruitment from this library changes as a function of the imposed biomechanical constraints. Our findings enhance understanding of the neural control of gait and may inform biofeedback strategies to improve synergy recruitment after neurological injury.
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Affiliation(s)
- Alyssa M Spomer
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States
| | - Robin Z Yan
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States
| | - Michael H Schwartz
- James R. Gage Center for Gait & Motion Analysis, Gillette Children's Specialty Healthcare, Saint Paul, Minnesota, United States
- Department of Orthopedic Surgery, University of Minnesota, Minneapolis, Minnesota, United States
| | - Katherine M Steele
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States
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Saito H, Yokoyama H, Sasaki A, Matsushita K, Nakazawa K. Variability of trunk muscle synergies underlying the multidirectional movements and stability trunk motor tasks in healthy individuals. Sci Rep 2023; 13:1193. [PMID: 36681745 PMCID: PMC9867711 DOI: 10.1038/s41598-023-28467-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 01/18/2023] [Indexed: 01/22/2023] Open
Abstract
Muscle synergy analysis is useful for investigating trunk coordination patterns based on the assumption that the central nervous system reduces the dimensionality of muscle activation to simplify movement. This study aimed to quantify the variability in trunk muscle synergy during various trunk motor tasks in healthy participants to provide reference data for evaluating trunk control strategies in patients and athletes. Sixteen healthy individuals performed 11 trunk movement and stability tasks with electromyography (EMG) recording of their spinal and abdominal muscles (6 bilaterally). Non-negative matrix factorization applied to the concatenated EMG of all tasks identified the five trunk muscle synergies (W) with their corresponding temporal patterns (C). The medians of within-cluster similarity defined by scalar products in W and rmax coefficient using the cross-correlation function in C were 0.73-0.86 and 0.64-0.75, respectively, while the inter-session similarities were 0.81-0.96 and 0.74-0.84, respectively. However, the lowest and highest values of both similarity indices were broad, reflecting the musculoskeletal system's redundancy within and between participants. Furthermore, the significant differences in the degree of variability between the trunk synergies may represent the different neural features of synergy organization and strategies to overcome the various mechanical demands of a motor task.
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Affiliation(s)
- Hiroki Saito
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Department of Physical Therapy, Tokyo University of Technology, Tokyo, Japan
| | - Hikaru Yokoyama
- Institute of Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan.
| | - Atsushi Sasaki
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | | | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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Chen X, Dong X, Feng Y, Jiao Y, Yu J, Song Y, Li X, Zhang L, Hou P, Xie P. Muscle activation patterns and muscle synergies reflect different modes of coordination during upper extremity movement. Front Hum Neurosci 2023; 16:912440. [PMID: 36741782 PMCID: PMC9889926 DOI: 10.3389/fnhum.2022.912440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 11/28/2022] [Indexed: 01/20/2023] Open
Abstract
A core issue in motor control is how the central nervous system generates and selects the muscle activation patterns necessary to achieve a variety of behaviors and movements. Extensive studies have verified that it is the foundation to induce a complex movement by the modular combinations of several muscles with a synergetic relationship. However, a few studies focus on the synergetic similarity and dissimilarity among different types of movements, especially for the upper extremity movements. In this study, we introduced the non-negative matrix factorization (NMF) method to explore the muscle activation patterns and synergy structure under 6 types of movements, involving the hand open (HO), hand close (HC), wrist flexion (WF), wrist extension (WE), supination (SU), and pronation (PR). For this, we enrolled 10 healthy subjects to record the electromyography signal for NMF calculation. The results showed a highly modular similarity of the muscle synergy among subjects under the same movement. Furthermore, Spearman's correlation analysis indicated significant similarities among HO-WE, HO-SU, and WE-SU (p < 0.001). Additionally, we also found shared synergy and special synergy in activation patterns among different movements. This study confirmed the theory of modular structure in the central nervous system, which yields a stable synergetic pattern under the same movement. Our findings on muscle synergy will be of great significance to motor control and even to clinical assessment techniques.
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Affiliation(s)
- Xiaoling Chen
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China,Key Laboratory of Intelligent Rehabilitation and Neuromodulation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China
| | - Xiaojiao Dong
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China
| | - Yange Feng
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China
| | - Yuntao Jiao
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China
| | - Jian Yu
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China
| | - Yan Song
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China
| | - Xinxin Li
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China
| | - Lijie Zhang
- School of Mechanical Engineering, Yanshan University, Qinhuangdao, Hebei, China
| | - Peiguo Hou
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China,Peiguo Hou,
| | - Ping Xie
- Key Laboratory of Measurement Technology and Instrumentation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China,Key Laboratory of Intelligent Rehabilitation and Neuromodulation of Hebei Province, School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei, China,*Correspondence: Ping Xie,
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Zhao K, Zhang Z, Wen H, Scano A. Number of trials and data structure affect the number and components of muscle synergies in upper-limb reaching movements. Physiol Meas 2022; 43. [PMID: 36195081 DOI: 10.1088/1361-6579/ac9773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/04/2022] [Indexed: 02/07/2023]
Abstract
Objective.Due to the variability of human movements, muscle activations vary among trials and subjects. However, few studies investigated how data organization methods for addressing variability impact the extracted muscle synergies.Approach.Fifteen healthy subjects performed a large set of upper limb multi-directional point-to-point reaching movements. Then, the study extracted muscle synergies under different data settings and investigated how data structure prior to synergy extraction, namely concatenation, averaging, and single trial, the number of considered trials, and the number of reaching directions affected the number and components of muscle synergies.Main results.The results showed that the number and components of synergies were significantly affected by the data structure. The concatenation method identified the highest number of synergies, and the averaging method usually found a smaller number of synergies. When the concatenated trials or reaching directions was lower than a minimum value, the number of synergies increased with the increase of the number of trials or reaching directions; however, when the number of trials or reaching directions reached a threshold, the number of synergies was usually constant or with less variation even when novel directions and trials were added. Similarity analysis also showed a slight increase when the number of trials or reaching directions was lower than a threshold. This study recommends that at least five trials and four reaching directions and the concatenation method are considered in muscle synergies analysis during upper limb tasks.Significance.This study makes the researchers focus on the variability analysis induced by the diseases rather than the techniques applied for synergies analysis and promotes applications of muscle synergies in clinical scenarios.
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Affiliation(s)
- Kunkun Zhao
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing, People's Republic of China.,School of Mechanical Engineering, Southeast University, Nanjing, People's Republic of China
| | - Zhisheng Zhang
- School of Mechanical Engineering, Southeast University, Nanjing, People's Republic of China
| | - Haiying Wen
- School of Mechanical Engineering, Southeast University, Nanjing, People's Republic of China
| | - Alessandro Scano
- UOS STIIMA Lecco-Human-Centered, Smart & Safe, Living Environment, Italian National Research Council (CNR), Via Previati 1/E, 23900 Lecco, Italy
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Oshima A, Nakamura Y, Kamibayashi K. Modulation of Muscle Synergies in Lower-Limb Muscles Associated With Split-Belt Locomotor Adaptation. Front Hum Neurosci 2022; 16:852530. [PMID: 35845245 PMCID: PMC9279664 DOI: 10.3389/fnhum.2022.852530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Humans have great locomotor adaptability to environmental demands, which has been investigated using a split-belt treadmill with belts on both the left and right sides. Thus far, neuromuscular control in split-belt locomotor adaptation has been evaluated by analyzing muscle activities at the individual muscle level. Meanwhile, in the motor control field, the muscle synergy concept has been proposed. Muscle synergies are considered the fundamental building blocks of movement and are groups of coactive muscles and time-varying activation patterns, thereby, reflecting the neurophysiological characteristics of movement. To date, it remains unclear how such muscle synergies change during the adaptation and de-adaptation processes on the split-belt treadmill. Hence, we chronologically extracted muscle synergies while walking on the split-belt treadmill and examined changes in the number, muscle weightings, and temporal activation patterns of muscle synergies. Twelve healthy young males participated, and surface electromyography (EMG) signals were recorded bilaterally from 13 lower-limb muscles. Muscle synergies were extracted by applying non-negative matrix factorization to the EMG data of each leg. We found that during split-belt walking, the number of synergies in the slow leg increased while an extra synergy appeared and disappeared in the fast leg. Additionally, the areas under the temporal activation patterns in several synergies in both legs decreased. When both belts returned to the same speed, a decrease in the number of synergies and an increase in the areas under the temporal activation patterns of several synergies were temporally shown in each leg. Subsequently, the number of synergies and the areas under the temporal activation patterns returned to those of normal walking before split-belt walking. Thus, changes in the number, muscle weightings, and temporal activation patterns of synergies were noted in the split-belt locomotor adaptation, suggesting that the adaptation and de-adaptation occurred at the muscle synergy level.
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Affiliation(s)
- Atsushi Oshima
- Graduate School of Health and Sports Science, Doshisha University, Kyoto, Japan
- Research Fellow of the Japan Society for the Promotion of Science, Tokyo, Japan
| | - Yasuo Nakamura
- Faculty of Health and Sports Science, Doshisha University, Kyoto, Japan
| | - Kiyotaka Kamibayashi
- Faculty of Health and Sports Science, Doshisha University, Kyoto, Japan
- *Correspondence: Kiyotaka Kamibayashi,
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12
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Kutsuzawa K, Hayashibe M. Motor synergy generalization framework for new targets in multi-planar and multi-directional reaching task. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211721. [PMID: 35620009 PMCID: PMC9114934 DOI: 10.1098/rsos.211721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 04/11/2022] [Indexed: 05/03/2023]
Abstract
Humans can rapidly adapt to new situations, even though they have redundant degrees of freedom (d.f.). Previous studies in neuroscience revealed that human movements could be accounted for by low-dimensional control signals, known as motor synergies. Many studies have suggested that humans use the same repertories of motor synergies among similar tasks. However, it has not yet been confirmed whether the combinations of motor synergy repertories can be re-used for new targets in a systematic way. Here we show that the combination of motor synergies can be generalized to new targets that each repertory cannot handle. We use the multi-directional reaching task as an example. We first trained multiple policies with limited ranges of targets by reinforcement learning and extracted sets of motor synergies. Finally, we optimized the activation patterns of sets of motor synergies and demonstrated that combined motor synergy repertories were able to reach new targets that were not achieved with either original policies or single repertories of motor synergies. We believe this is the first study that has succeeded in motor synergy generalization for new targets in new planes, using a full 7-d.f. arm model, which is a realistic mechanical environment for general reaching tasks.
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Affiliation(s)
- Kyo Kutsuzawa
- Department of Robotics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Mitsuhiro Hayashibe
- Department of Robotics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
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13
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Rosenblum U, Melzer I, Zeilig G, Plotnik M. Muscle activation profile is modulated by unexpected balance loss in walking. Gait Posture 2022; 93:64-72. [PMID: 35091185 DOI: 10.1016/j.gaitpost.2022.01.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 12/30/2021] [Accepted: 01/16/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND During an unexpected loss of balance, avoiding a fall requires people to readjust their footing rapidly and effectively. A deeper understanding of muscle activation patterns in response to unexpected balance loss will provide insights into the mechanisms of balance recovery responses. This could have implications for treatment of people with balance deficits. RESEARCH QUESTION Explore the differences in balance recovery responses to perturbations in different phases of the gait cycle (single-support vs. double-support) in terms of biomechanical behavior (i.e., stepping and dynamic stability characteristics) and lower-limb muscle activation patterns. METHODS Muscle activation patterns of the ankle and knee muscles and muscle fiber type recruitment resulting from unannounced, mediolateral (i.e., right/left) horizontal-surface perturbations during walking was investigated in twenty healthy adults (27.00 ± 2.79 years, ten females). Surface electromyography (sEMG) total spectral power for specific frequency bands (40-60 Hz, 60-150 Hz, 150-250 Hz, 250-400 Hz and 400-1000 Hz), from tibialis anterior (TA) and vastus lateralis (VL) muscles were analyzed. Three mixed-effects models assessed behavioral and lower-limb muscle activation patterns resulting from perturbations in the gait cycle's single- and double-support phases. Statistical significance was set a priori at p < 0.05. RESULTS Compared to non-perturbed walking, we found a significant increase in the total spectral power of lower-extremity muscles during the first three seconds after perturbation. During the double-support phase of gait, we found a different muscle fiber type recruitment pattern between VL and TA muscles. However, there were no significant differences between VL and TA muscles for perturbations implemented in single-support phases. SIGNIFICANCE Our findings support the notion that muscle operating frequency is modulated in real-time to fit functional goal requirements, such as a rapid change of footing in response to unexpected loss of balance in single and double-support phases of gait.
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Affiliation(s)
- Uri Rosenblum
- Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Tel Hashomer, Israel; Department of Physical Therapy, Recanati School for Community Health Professions, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel.
| | - Itshak Melzer
- Department of Physical Therapy, Recanati School for Community Health Professions, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Gabi Zeilig
- Department of Neurological Rehabilitation, Sheba Medical Center, Tel HaShomer, Israel; Department of Physical and Rehabilitation Medicine, Faculty of Medicine, Tel Aviv University, Israel; School of Health Professions, Ono Academic College, Kiryat Ono, Israel
| | - Meir Plotnik
- Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Tel Hashomer, Israel; Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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14
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The Existence of Shared Muscle Synergies Underlying Perturbed and Unperturbed Gait Depends on Walking Speed. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12042135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Muscle synergy theory assumes that the central nervous system generates a wide range of complex motor outputs by recruiting muscle synergies with different strengths and timings. The current understanding is that a common set of muscle synergies underlies unperturbed as well as perturbed walking at self-selected speeds. However, it is not known whether this is the case for substantially slower walking. The aim of this study was to investigate whether a shared set of muscle synergies underlies balance recovery responses following inward- and outward-directed perturbations in the mediolateral direction at various perturbation onsets and walking speeds. Twelve healthy subjects walked at three walking speeds (0.4, 0.6, and 0.8 m/s) on a treadmill while perturbations were applied to the pelvis using the balance assessment robot. A set of sixteen EMG signals, i.e., eight muscles per leg, was measured and decomposed into muscle synergies and weighting curves using non-negative matrix factorization. The muscles included were left and right tibialis anterior, soleus, gastrocnemius medialis, gastrocnemius lateralis, rectus femoris, hamstring, gluteus medius, and gluteus maximus. In general, four muscle synergies were needed to adequately reconstruct the data. Muscle synergies were similar for unperturbed and perturbed walking at a high walking speed (0.8 m/s). However, the number of similar muscle synergies between perturbed and unperturbed walking was significantly lower for low walking speeds (0.4 and 0.6 m/s). These results indicate that shared muscle synergies underlying perturbed and unperturbed walking are less present during slow walking compared to fast walking.
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15
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O'Reilly D, Delis I. A network information theoretic framework to characterise muscle synergies in space and time. J Neural Eng 2022; 19. [PMID: 35108699 DOI: 10.1088/1741-2552/ac5150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/02/2022] [Indexed: 11/12/2022]
Abstract
Objective Current approaches to muscle synergy extraction rely on linear dimensionality reduction algorithms that make specific assumptions on the underlying signals. However, to capture nonlinear time varying, large-scale but also muscle-specific interactions, a more generalised approach is required. Approach Here we developed a novel framework for muscle synergy extraction that relaxes model assumptions by using a combination of information- and network theory and dimensionality reduction. We first quantify informational dynamics between muscles, time-samples or muscle-time pairings using a novel mutual information formulation. We then model these pairwise interactions as multiplex networks and identify modules representing the network architecture. We employ this modularity criterion as the input parameter for dimensionality reduction, which verifiably extracts the identified modules, and also to characterise salient structures within each module. Main results This novel framework captures spatial, temporal and spatiotemporal interactions across two benchmark datasets of reaching movements, producing distinct spatial groupings and both tonic and phasic temporal patterns. Readily interpretable muscle synergies spanning multiple spatial and temporal scales were identified, demonstrating significant task dependence, ability to capture trial-to-trial fluctuations and concordance across participants. Furthermore, our framework identifies submodular structures that represent the distributed networks of co-occurring signal interactions across scales. Significance The capabilities of this framework are illustrated through the concomitant continuity with previous research and novelty of the insights gained. Several previous limitations are circumvented including the extraction of functionally meaningful and multiplexed pairwise muscle couplings under relaxed model assumptions. The extracted synergies provide a holistic view of the movement while important details of task performance are readily interpretable. The identified muscle groupings transcend biomechanical constraints and the temporal patterns reveal characteristics of fundamental motor control mechanisms. We conclude that this framework opens new opportunities for muscle synergy research and can constitute a bridge between existing models and recent network-theoretic endeavours.
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Affiliation(s)
- David O'Reilly
- University of Leeds, Faculty of Biological sciences, Leeds, LS2 9JT, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Ioannis Delis
- University of Leeds, Faculty of Biological sciences, Leeds, Leeds, LS2 9JT, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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16
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Saito H, Yokoyama H, Sasaki A, Kato T, Nakazawa K. Flexible Recruitments of Fundamental Muscle Synergies in the Trunk and Lower Limbs for Highly Variable Movements and Postures. SENSORS (BASEL, SWITZERLAND) 2021; 21:6186. [PMID: 34577394 PMCID: PMC8472977 DOI: 10.3390/s21186186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 11/16/2022]
Abstract
The extent to which muscle synergies represent the neural control of human behavior remains unknown. Here, we tested whether certain sets of muscle synergies that are fundamentally necessary across behaviors exist. We measured the electromyographic activities of 26 muscles, including bilateral trunk and lower limb muscles, during 24 locomotion, dynamic and static stability tasks, and we extracted the muscle synergies using non-negative matrix factorization. Our results show that 13 muscle synergies that may have unique functional roles accounted for almost all 24 tasks by combinations of single and/or merging of synergies. Therefore, our results may support the notion of the low dimensionality in motor outputs, in which the central nervous system flexibly recruits fundamental muscle synergies to execute diverse human behaviors. Further studies are required to validate the neural representation of the fundamental components of muscle synergies.
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Affiliation(s)
- Hiroki Saito
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; (H.S.); (H.Y.); (A.S.); (T.K.)
- Department of Physical Therapy, Tokyo University of Technology, Ota, Tokyo 144-8535, Japan
| | - Hikaru Yokoyama
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; (H.S.); (H.Y.); (A.S.); (T.K.)
| | - Atsushi Sasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; (H.S.); (H.Y.); (A.S.); (T.K.)
- Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda, Tokyo 102-0083, Japan
| | - Tatsuya Kato
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; (H.S.); (H.Y.); (A.S.); (T.K.)
- Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda, Tokyo 102-0083, Japan
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan; (H.S.); (H.Y.); (A.S.); (T.K.)
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17
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Primitive muscle synergies reflect different modes of coordination in upper limb motions. Med Biol Eng Comput 2021; 59:2153-2163. [PMID: 34482509 DOI: 10.1007/s11517-021-02429-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 08/09/2021] [Indexed: 10/20/2022]
Abstract
The motor system relies on the recruitment of motor modules to perform various movements. Muscle synergies are the modules used by the central nervous system to simplify the control of complex motor tasks. In this paper, we aim to explore the primitive synergies to reflect different modes of coordination in upper limb motions. Muscle synergies and corresponding activation coefficients were extracted via non-negative matrix factorization from the electromyography signals of three basic and four complex upper limb motions in sagittal plane and coronal plane. Similarities of muscle synergies and activation coefficients between different tasks and different subjects were compared. Moreover, we used network theory to assess the coordination between multiple muscles and to elucidate the neural implementation of muscle synergies. The results showed that the combination of different sets of primitive muscle synergies can achieve complex motions in different planes. The muscle synergy network topology differed significantly between different tasks. We also demonstrated the potential of this study for the understanding of human motor control mechanism and implications for neurorehabilitation.
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18
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Manzano M, Serrancolí G. A factorization-based algorithm to predict EMG data using only kinematics information. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3463. [PMID: 33835726 DOI: 10.1002/cnm.3463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 02/16/2021] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
EMG analyses have several applications, such as identifying muscle excitation patterns during rehabilitation or training plans, or controlling EMG-driven devices. However, experimental measurements can be time consuming or difficult to obtain. This study presents a simple algorithm to predict EMG signals that can be applied in real time during running, given only the instantaneous vector of kinematics. We hypothesize that the factorization of the kinematics of the skeleton together with the EMG data of calibration subjects could be used to predict EMG data of another subject only using the kinematic information. The results showed that EMG signals of lower-limb muscles can be predicted accurately in less than a second using this method. Correlation coefficients between predicted and experimental EMG signals were higher than 0.7 in 10 out of 11 muscles for most prediction trials and subjects, and their overall median value was higher than 0.8. These values confirm that this method could be used to accurately predict EMG signals in real time when only kinematics are measured.
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Affiliation(s)
- Marta Manzano
- Department of Mechanical Engineering, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Gil Serrancolí
- Department of Mechanical Engineering, Universitat Politècnica de Catalunya, Barcelona, Spain
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19
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Cano Porras D, Jacobs JV, Inzelberg R, Bahat Y, Zeilig G, Plotnik M. Patterns of whole-body muscle activations following vertical perturbations during standing and walking. J Neuroeng Rehabil 2021; 18:75. [PMID: 33957953 PMCID: PMC8101216 DOI: 10.1186/s12984-021-00836-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 02/10/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Falls commonly occur due to losses of balance associated with vertical body movements (e.g. reacting to uneven ground, street curbs). Research, however, has focused on horizontal perturbations, such as forward and backward translations of the standing surface. This study describes and compares muscle activation patterns following vertical and horizontal perturbations during standing and walking, and investigates the role of vision during standing postural responses. METHODS Fourteen healthy participants (ten males; 27±4 years-old) responded to downward, upward, forward, and backward perturbations while standing and walking in a virtual reality (VR) facility containing a moveable platform with an embedded treadmill; participants were also exposed to visual perturbations in which only the virtual scenery moved. We collected bilateral surface electromyography (EMG) signals from 8 muscles (tibialis anterior, rectus femoris, rectus abdominis, external oblique, gastrocnemius, biceps femoris, paraspinals, deltoids). Parameters included onset latency, duration of activation, and activation magnitude. Standing perturbations comprised dynamic-camera (congruent), static-camera (incongruent) and eyes-closed sensory conditions. ANOVAs were used to compare the effects of perturbation direction and sensory condition across muscles. RESULTS Vertical perturbations induced longer onset latencies and shorter durations of activation with lower activation magnitudes in comparison to horizontal perturbations (p<0.0001). Downward perturbations while standing generated earlier activation of anterior muscles to facilitate flexion (for example, p=0.0005 and p=0.0021 when comparing the early activators, rectus femoris and tibialis anterior, to a late activator, the paraspinals), whereas upward perturbations generated earlier activation of posterior muscles to facilitate extension (for example, p<0.0001 and p=0.0004, when comparing the early activators, biceps femoris and gastrocnemius, to a late activator, the rectus abdominis). Static-camera conditions induced longer onset latencies (p=0.0085 and p<0.0001 compared to eyes-closed and dynamic-camera conditions, respectively), whereas eyes-closed conditions induced longer durations of activation (p=0.0001 and p=0.0008 compared to static-camera and dynamic-camera, respectively) and larger activation magnitudes. During walking, downward perturbations promptly activated contralateral trunk and deltoid muscles (e.g., p=0.0036 for contralateral deltoid versus a late activator, the ipsilateral tibialis anterior), and upward perturbations triggered early activation of trunk flexors (e.g., p=0.0308 for contralateral rectus abdominis versus a late activator, the ipsilateral gastrocnemius). Visual perturbations elicited muscle activation in 67.7% of trials. CONCLUSION Our results demonstrate that vertical (vs. horizontal) perturbations generate unique balance-correcting muscle activations, which were consistent with counteracting vertical body extension induced by downward perturbations and vertical body flexion induced by upward perturbations. Availability of visual input appears to affect response efficiency, and incongruent visual input can adversely affect response triggering. Our findings have clinical implications for the design of robotic exoskeletons (to ensure user safety in dynamic balance environments) and for perturbation-based balance and gait rehabilitation.
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Affiliation(s)
- Desiderio Cano Porras
- Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Ramat Gan, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Perception and Action in Complex Environments, Marie Curie International Training Network, European Union's Horizons 2020 Research and Innovation Program, Brussels, Belgium.,Brightlands Institute for Smart Society-BISS, Maastricht University, Maastricht, The Netherlands
| | - Jesse V Jacobs
- Rehabilitation and Movement Science, University of Vermont, Burlington, VT, USA
| | - Rivka Inzelberg
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.,Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Applied Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot, Israel
| | - Yotam Bahat
- Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Ramat Gan, Israel
| | - Gabriel Zeilig
- Department of Neurological Rehabilitation, Sheba Medical Center, Tel HaShomer, Ramat Gan, Israel.,Department of Physical and Rehabilitation Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Meir Plotnik
- Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Ramat Gan, Israel. .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel. .,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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20
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Ebied A, Kinney-Lang E, Escudero J. Higher order tensor decomposition for proportional myoelectric control based on muscle synergies. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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21
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Arora T, Musselman KE, Lanovaz JL, Linassi G, Arnold C, Milosavljevic S, Oates A. Reactive balance responses to an unexpected slip perturbation in individuals with incomplete spinal cord injury. Clin Biomech (Bristol, Avon) 2020; 78:105099. [PMID: 32653743 DOI: 10.1016/j.clinbiomech.2020.105099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 05/05/2020] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Frequent falls while walking among individuals with incomplete spinal cord injury may suggest impairments in reactive balance control; however, reactive balance control during walking has not been studied in this population. The objective was to compare reactive balance control with respect to changes in margin of stability, onset of arm and heel responses, and onset and magnitude of muscle activity following an unexpected slip perturbation in individuals with incomplete spinal cord injury and able-bodied individuals. METHODS Kinematic and electromyography data were obtained during normal walking and one unexpected slip. Changes in margin of stability following a compensatory or aborted step, onset of arms and trail heel responses, and onset and magnitude of activation of the tibialis anterior, soleus and gluteus medius were calculated. Multivariate analyses compared responses between incomplete spinal cord injury and able-bodied groups. FINDINGS Data from 16 participants with incomplete spinal cord injury (all American Spinal Injury Association Impairment Scale Grade D, 8 with tetraplegia) and 13 age-and-sex matched able-bodied individuals were included. Individuals with incomplete spinal cord injury demonstrated limited ability to increase margin of stability in the lateral direction during a compensatory or aborted step, and a smaller magnitude of soleus activity compared to able-bodied individuals. INTERPRETATION There are limitations in reactive balance control of individuals with incomplete spinal cord injury, which may be a reason for the high frequency of falls in this population. Reactive balance assessment should be included as a component of routine balance assessment and fall avoidance strategies in this population.
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Affiliation(s)
- Tarun Arora
- Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA; College of Medicine, University of Saskatchewan, Saskatoon, Canada; School of Rehabilitation Science, University of Saskatchewan, Saskatoon, Canada.
| | - Kristin E Musselman
- College of Medicine, University of Saskatchewan, Saskatoon, Canada; School of Rehabilitation Science, University of Saskatchewan, Saskatoon, Canada; Toronto Rehabilitation Institute, University Health Network, Toronto, Canada; Dept. of Physical Therapy, Faculty of Medicine, University of Toronto, Canada
| | - Joel L Lanovaz
- College of Kinesiology, University of Saskatchewan, Saskatchewan, Canada
| | - Gary Linassi
- College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Catherine Arnold
- College of Medicine, University of Saskatchewan, Saskatoon, Canada; School of Rehabilitation Science, University of Saskatchewan, Saskatoon, Canada
| | - Stephan Milosavljevic
- College of Medicine, University of Saskatchewan, Saskatoon, Canada; School of Rehabilitation Science, University of Saskatchewan, Saskatoon, Canada
| | - Alison Oates
- College of Kinesiology, University of Saskatchewan, Saskatchewan, Canada
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22
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Bohm S, Mandla-Liebsch M, Mersmann F, Arampatzis A. Exercise of Dynamic Stability in the Presence of Perturbations Elicit Fast Improvements of Simulated Fall Recovery and Strength in Older Adults: A Randomized Controlled Trial. Front Sports Act Living 2020; 2:52. [PMID: 33345043 PMCID: PMC7739602 DOI: 10.3389/fspor.2020.00052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/16/2020] [Indexed: 12/21/2022] Open
Abstract
Age-related impairments of reactive motor responses to postural threats and reduced muscular capacities of the legs are key factors for the higher risk of falling in older people. It has been evidenced that a training of dynamic stability in the presence of perturbations has the potential to improve these deficits. However, the time course of training effects during such interventions is poorly understood. The purpose of this parallel-group study was to investigate the temporal adaptation dynamics of the balance recovery performance and leg strength during a dynamic stability training. Forty-two healthy older adults (65–85 years) were randomly assigned to a training (n = 27, analyzed n = 18) or control group (n = 15, n = 14). The training was conducted in a group setting for 6 weeks (3×/week, 45 min). The exercises focused on the mechanism of stability control (i.e., modulation of the base of support and segment counter-rotations around the center of mass) during standing, stepping, and jumping on unstable surfaces with a high balance intensity. Before, after 3 and after 6 weeks, the maximum plantar flexion moment and the knee extension moment were assessed. The recovery performance was evaluated by a simulated forward fall (lean-and-release test) and the margin of stability concept. The margin of stability at release decreased significantly after 3 weeks of training (34%, effect size g = 0.79), which indicates fast improvements of balance recovery performance. The margin of stability further decreased after week 6 (53%, g = 1.21), yet the difference between weeks 3 and 6 was not significant. Furthermore, the training led to significant increases in the plantar flexion moment after weeks 3 (12%, g = 0.72) and 6 (13%, g = 0.75) with no significant difference between weeks. For the knee extension moment, a significant increase was found only after week 6 (11%, g = 1.07). The control group did not show any significant changes. This study provides evidence that a challenging training of dynamic stability in the presence of perturbations can improve balance recovery performance and leg strength of older adults already after a few weeks. Therefore, short-term training interventions using this paradigm may be an effective strategy for fall prevention in the elderly population, particularly when intervention time is limited.
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Affiliation(s)
- Sebastian Bohm
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Martin Mandla-Liebsch
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Falk Mersmann
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Adamantios Arampatzis
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
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23
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Singh RE, White G, Delis I, Iqbal K. Alteration of muscle synergy structure while walking under increased postural constraints. COGNITIVE COMPUTATION AND SYSTEMS 2020. [DOI: 10.1049/ccs.2019.0021] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Rajat Emanuel Singh
- Department of Systems EngineeringUniversity of Arkansas at Little RockARUSA
- School of Counseling Human Performance & RehabilitationUniversity of Arkansas at Little RockARUSA
| | - Gannon White
- Department of KinesiologyColorado Mesa UniversityCOUSA
| | | | - Kamran Iqbal
- Department of Systems EngineeringUniversity of Arkansas at Little RockARUSA
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Age-Related Differences in Muscle Synergy Organization during Step Ascent at Different Heights and Directions. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10061987] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aim of this study was to explore the underlying age-related differences in dynamic motor control during different step ascent conditions using muscle synergy analysis. Eleven older women (67.0 y ± 2.5) and ten young women (22.5 y ± 1.6) performed stepping in forward and lateral directions at step heights of 10, 20 and 30 cm. Surface electromyography was obtained from 10 lower limb and torso muscles. Non-negative matrix factorization was used to identify sets of (n) synergies across age groups and stepping conditions. In addition, variance accounted for (VAF) by the detected number of synergies was compared to assess complexity of motor control. Finally, correlation coefficients of muscle weightings and between-subject variability of the temporal activation patterns were calculated and compared between age groups and stepping conditions. Four synergies accounted for >85% VAF across age groups and stepping conditions. Age and step height showed a significant negative correlation with VAF during forward stepping but not lateral stepping, with lower VAF indicating higher synergy complexity. Muscle weightings showed higher similarity across step heights in older compared to young women. Neuromuscular control of young and community-dwelling older women could not be differentiated based on the number of synergies extracted. Additional analyses of synergy structure and complexity revealed subtle age- and step-height-related differences, indicating that older women rely on more complex neuromuscular control strategies.
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25
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Angular momentum regulation may dictate the slip severity in young adults. PLoS One 2020; 15:e0230019. [PMID: 32163463 PMCID: PMC7067419 DOI: 10.1371/journal.pone.0230019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 02/19/2020] [Indexed: 11/19/2022] Open
Abstract
Falls cause negative impacts on society and the economy. Slipping is a common initiating event for falling. Yet, individuals differ in their ability to recover from slips. Persons experiencing mild slips can accommodate the perturbation without falling, whereas severe slipping is associated with inadequate or slow pre- or post-slip control that make these individuals more prone to fall. Knowing the discrepancies between mild and severe slippers in kinematic and kinetic variables improves understanding of adverse control responsible for severe slipping. This study examined differences across these participants with respect to center of mass (COM) height, sagittal angular momentum (H), upper body kinematics, and the duration of single/double phase. Possible causality of such relationships was also studied by observing the time-lead of the deviations. Twenty healthy young adults performed walking trials in dry and slippery conditions. They were classified into mild and severe slippers based on their heel slipping speed. No inter-group differences were observed in the upper extremity kinematics. It was found that mild and severe slippers do not differ in the studied variables during normal gait; however, they do show significant differences through slipping. Compared to mild slippers, sever slippers lowered their COM height following a slip, presented higher H, and shortened their single support phase (p-value<0.05 for all). Based on the time-lead observed in H over all other variables suggests that failure to control angular momentum may influence slip severity.
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26
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Hinnekens E, Berret B, Do MC, Teulier C. Modularity underlying the performance of unusual locomotor tasks inspired by developmental milestones. J Neurophysiol 2019; 123:496-510. [PMID: 31825715 DOI: 10.1152/jn.00662.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Motor behaviors are often hypothesized to be set up from the combination of a small number of modules encoded in the central nervous system. These modules are thought to combine such that a variety of motor tasks can be realized, from reproducible tasks such as walking to more unusual locomotor tasks that typically exhibit more step-by-step variability. We investigated the impact of step-by-step variability on the modular architecture of unusual tasks compared with walking. To this aim, 20 adults had to perform walking and two unusual modes of locomotion inspired by developmental milestones (cruising and crawling). Sixteen surface electromyography (EMG) signals were recorded to extract both spatial and temporal modules. Modules were extracted from both averaged and nonaveraged (i.e., single step) EMG signals to assess the significance of step-to-step variability when participants practiced such unusual locomotor tasks. The number of modules extracted from averaged data was similar across tasks, but a higher number of modules was required to reconstruct nonaveraged EMG data of the unusual tasks. Although certain walking modules were shared with cruising and crawling, task-specific modules were necessary to account for the muscle patterns underlying these unusual locomotion modes. These results highlight a more complex modularity (e.g., more modules) for cruising and crawling compared with walking, which was only apparent when the step-to-step variability of EMG patterns was considered. This suggests that considering nonaveraged data is relevant when muscle modularity is studied, especially in motor tasks with high variability as in motor development.NEW & NOTEWORTHY This study addresses the general question of modularity in locomotor control. We demonstrate for the first time the importance of intraindividual variability in the muscle modularity of unusual locomotor behaviors that exhibit greater step-by-step variability than standard walking. Crawling and cruising, the unusual locomotor modes considered, are based on a more complex modular organization than walking. More spatial and temporal modules, task specific or shared with walking modules, are needed to reconstruct muscle patterns.
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Affiliation(s)
- Elodie Hinnekens
- Laboratoire Complexité, Innovations, Activités Motrices et Sportives (CIAMS), Université Paris-Sud, Université Paris-Saclay, Orsay, France.,CIAMS, Université d'Orléans, Orléans, France
| | - Bastien Berret
- Laboratoire Complexité, Innovations, Activités Motrices et Sportives (CIAMS), Université Paris-Sud, Université Paris-Saclay, Orsay, France.,CIAMS, Université d'Orléans, Orléans, France.,Institut Universitaire de France, Paris, France
| | - Manh-Cuong Do
- Laboratoire Complexité, Innovations, Activités Motrices et Sportives (CIAMS), Université Paris-Sud, Université Paris-Saclay, Orsay, France.,CIAMS, Université d'Orléans, Orléans, France
| | - Caroline Teulier
- Laboratoire Complexité, Innovations, Activités Motrices et Sportives (CIAMS), Université Paris-Sud, Université Paris-Saclay, Orsay, France.,CIAMS, Université d'Orléans, Orléans, France
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27
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Nazifi MM, Beschorner KE, Hur P. Do Walking Muscle Synergies Influence Propensity of Severe Slipping? Front Hum Neurosci 2019; 13:383. [PMID: 31787887 PMCID: PMC6853891 DOI: 10.3389/fnhum.2019.00383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/14/2019] [Indexed: 11/19/2022] Open
Abstract
Slipping is frequently responsible for falling injuries. Preventing slips, and more importantly severe slips, is of importance in fall prevention. Our previous study characterized mild slipping and severe slipping by the analysis of muscle synergies. Significant discrepancies in motor control of slipping have been observed between mild and severe slippers. We are further interested in whether differences exist in baseline motor control patterns between persons who experience mild and severe slips when exposed to a slippery contaminant. This study investigated walking with a muscle synergy approach to detect if walking muscle synergies differ between groups experiencing different slip severities. Twenty healthy young adults (eight mild slippers and 12 severe slippers) participated in this study and their muscle synergies of walking were extracted. Muscle synergy analysis showed that mild slippers had a higher contribution of hamstring and quadriceps during walking while severe slippers had increased contribution of the tibialis group. This study provides novel information that may contribute to identifying diagnostic techniques for identifying persons or populations with a high risk of fall based on their walking patterns.
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Affiliation(s)
- Mohammad Moein Nazifi
- Human Rehabilitation Group, Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States
| | - Kurt E Beschorner
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Industrial Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Pilwon Hur
- Human Rehabilitation Group, Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States
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28
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Modular Organization of Muscle Synergies to Achieve Movement Behaviors. JOURNAL OF HEALTHCARE ENGINEERING 2019; 2019:8130297. [PMID: 31827741 PMCID: PMC6885185 DOI: 10.1155/2019/8130297] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 10/21/2019] [Indexed: 12/30/2022]
Abstract
Muscle synergy has been applied to comprehend how the central nervous system (CNS) controls movements for decades. However, it is not clear about the motion control mechanism and the relationship between motions and muscle synergies. In this paper, we designed two experiments to corroborate the hypothesis: (1) motions can be decomposed to motion primitives, which are driven by muscle synergy primitives and (2) variations of motion primitives in direction and scale are modulated by activation coefficients rather than muscle synergy primitives. Surface electromyographic (EMG) signals were recorded from nine muscles of the upper limb. Nonnegative matrix factorization (NMF) was applied to extract muscle synergy vectors and corresponding activation coefficients. We found that synergy structures of different movement patterns were similar (α=0.05). The motion modulation indexes (MMI) among movement patterns in reaching movements showed apparent differences. Merging coefficients and reconstructed similarity of synergies between simple motions and complex motions were significant. This study revealed the motion control mechanism of the CNS and provided a rehabilitation and evaluation method for patients with motor dysfunction in exercise and neuroscience.
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29
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Towards Real-Time Prediction of Freezing of Gait in Patients With Parkinson's Disease: Addressing the Class Imbalance Problem. SENSORS 2019; 19:s19183898. [PMID: 31509999 PMCID: PMC6767263 DOI: 10.3390/s19183898] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/05/2019] [Accepted: 09/08/2019] [Indexed: 01/06/2023]
Abstract
Freezing of gait (FoG) is a common motor symptom in patients with Parkinson's disease (PD). FoG impairs gait initiation and walking and increases fall risk. Intelligent external cueing systems implementing FoG detection algorithms have been developed to help patients recover gait after freezing. However, predicting FoG before its occurrence enables preemptive cueing and may prevent FoG. Such prediction remains challenging given the relative infrequency of freezing compared to non-freezing events. In this study, we investigated the ability of individual and ensemble classifiers to predict FoG. We also studied the effect of the ADAptive SYNthetic (ADASYN) sampling algorithm and classification cost on classifier performance. Eighteen PD patients performed a series of daily walking tasks wearing accelerometers on their ankles, with nine experiencing FoG. The ensemble classifier formed by Support Vector Machines, K-Nearest Neighbors, and Multi-Layer Perceptron using bagging techniques demonstrated highest performance (F1 = 90.7) when synthetic FoG samples were added to the training set and class cost was set as twice that of normal gait. The model identified 97.4% of the events, with 66.7% being predicted. This study demonstrates our algorithm's potential for accurate prediction of gait events and the provision of preventive cueing in spite of limited event frequency.
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30
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A single session of trip-specific training modifies trunk control following treadmill induced balance perturbations in stroke survivors. Gait Posture 2019; 70:222-228. [PMID: 30904789 PMCID: PMC6508877 DOI: 10.1016/j.gaitpost.2019.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 02/28/2019] [Accepted: 03/04/2019] [Indexed: 02/02/2023]
Abstract
BACKGROUND Individuals with stroke are at significant risk of falling. Trip-specific training is a targeted training approach that has been shown to reduce falls in older adults and amputees by enhancing the compensatory stepping response required to prevent a fall. Still, individuals with stroke have unique deficits (e.g. spasticity) which draws into question if this type of training will be effective for this population. OBJECTIVE Evaluate if a single session of trip-specific training can modify the compensatory stepping response (trunk movement, step length/duration, reaction time) of individuals with chronic stroke. METHODS Sixteen individuals with unilateral chronic stroke participated in a single session of trip-specific training consisting of 15 treadmill perturbations. A falls assessment consisting of 3 perturbations was completed before and after training. Recovery step kinematics measured during the pre- and post-test were compared using a repeated measures design. Furthermore, Fallers (those who experienced at least one fall during the pre- or post-test) were compared to Non-fallers. RESULTS Trip-specific training decreased trunk movement post perturbation. Specifically following training, Trunk flexion was 48 and 19 percent smaller on the small and medium perturbations at the end of the first compensatory step. Fallers (9 out of 16 subjects) post-training resembled Non-Fallers pre-training. Specifically, Trunk flexion at the completion of the first step during small and medium perturbations was not different between Fallers post-training and Non-Fallers pre-training. Still enthusiasm was tempered because Trunk flexion at the largest perturbation (where most falls occurred) was not changed and therefore total falls were not reduced as a result of this training. SIGNIFICANCE Our results indicate that trip-specific training modifies the dynamic falls response immediately following trip-like treadmill perturbations. However, the incidence of falls was not reduced with a single training session. Further study of the implications and length of the observed intervention effect are warranted.
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31
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Yufik YM. The Understanding Capacity and Information Dynamics in the Human Brain. ENTROPY 2019; 21:e21030308. [PMID: 33267023 PMCID: PMC7514789 DOI: 10.3390/e21030308] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/08/2019] [Accepted: 03/15/2019] [Indexed: 12/11/2022]
Abstract
This article proposes a theory of neuronal processes underlying cognition, focusing on the mechanisms of understanding in the human brain. Understanding is a product of mental modeling. The paper argues that mental modeling is a form of information production inside the neuronal system extending the reach of human cognition “beyond the information given” (Bruner, J.S., Beyond the Information Given, 1973). Mental modeling enables forms of learning and prediction (learning with understanding and prediction via explanation) that are unique to humans, allowing robust performance under unfamiliar conditions having no precedents in the past history. The proposed theory centers on the notions of self-organization and emergent properties of collective behavior in the neuronal substrate. The theory motivates new approaches in the design of intelligent artifacts (machine understanding) that are complementary to those underlying the technology of machine learning.
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Affiliation(s)
- Yan M Yufik
- Virtual Structures Research, Inc., Potomac, MD 20854, USA
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32
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Santuz A, Ekizos A, Janshen L, Mersmann F, Bohm S, Baltzopoulos V, Arampatzis A. Modular Control of Human Movement During Running: An Open Access Data Set. Front Physiol 2018; 9:1509. [PMID: 30420812 PMCID: PMC6216155 DOI: 10.3389/fphys.2018.01509] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/08/2018] [Indexed: 12/31/2022] Open
Abstract
The human body is an outstandingly complex machine including around 1000 muscles and joints acting synergistically. Yet, the coordination of the enormous amount of degrees of freedom needed for movement is mastered by our one brain and spinal cord. The idea that some synergistic neural components of movement exist was already suggested at the beginning of the 20th century. Since then, it has been widely accepted that the central nervous system might simplify the production of movement by avoiding the control of each muscle individually. Instead, it might be controlling muscles in common patterns that have been called muscle synergies. Only with the advent of modern computational methods and hardware it has been possible to numerically extract synergies from electromyography (EMG) signals. However, typical experimental setups do not include a big number of individuals, with common sample sizes of 5 to 20 participants. With this study, we make publicly available a set of EMG activities recorded during treadmill running from the right lower limb of 135 healthy and young adults (78 males and 57 females). Moreover, we include in this open access data set the code used to extract synergies from EMG data using non-negative matrix factorization (NMF) and the relative outcomes. Muscle synergies, containing the time-invariant muscle weightings (motor modules) and the time-dependent activation coefficients (motor primitives), were extracted from 13 ipsilateral EMG activities using NMF. Four synergies were enough to describe as many gait cycle phases during running: weight acceptance, propulsion, early swing, and late swing. We foresee many possible applications of our data that we can summarize in three key points. First, it can be a prime source for broadening the representation of human motor control due to the big sample size. Second, it could serve as a benchmark for scientists from multiple disciplines such as musculoskeletal modeling, robotics, clinical neuroscience, sport science, etc. Third, the data set could be used both to train students or to support established scientists in the perfection of current muscle synergies extraction methods. All the data is available at Zenodo (doi: 10.5281/zenodo.1254380).
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Affiliation(s)
- Alessandro Santuz
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Antonis Ekizos
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Lars Janshen
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Falk Mersmann
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sebastian Bohm
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Vasilios Baltzopoulos
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Adamantios Arampatzis
- Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.,Berlin School of Movement Science, Humboldt-Universität zu Berlin, Berlin, Germany
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33
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Pan B, Sun Y, Xie B, Huang Z, Wu J, Hou J, Liu Y, Huang Z, Zhang Z. Alterations of Muscle Synergies During Voluntary Arm Reaching Movement in Subacute Stroke Survivors at Different Levels of Impairment. Front Comput Neurosci 2018; 12:69. [PMID: 30186130 PMCID: PMC6111238 DOI: 10.3389/fncom.2018.00069] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 07/30/2018] [Indexed: 01/07/2023] Open
Abstract
Motor system uses muscle synergies as a modular organization to simplify the control of movements. Motor cortical impairments, such as stroke and spinal cord injuries, disrupt the orchestration of the muscle synergies and result in abnormal movements. In this paper, the alterations of muscle synergies in subacute stroke survivors were examined during the voluntary reaching movement. We collected electromyographic (EMG) data from 35 stroke survivors, ranging from Brunnstrom Stage III to VI, and 25 age-matched control subjects. Muscle synergies were extracted from the activity of 7 upper-limb muscles via nonnegative matrix factorization under the criterion of 95% variance accounted for. By comparing the structure of muscle synergies and the similarity of activation coefficients across groups, we can validate the increasing activation of pectoralis major muscle and the decreasing activation of elbow extensor of triceps in stroke groups. Furthermore, the similarity of muscle synergies was significantly correlated with the Brunnstrom Stage (R = 0.52, p < 0.01). The synergies of stroke survivors at Brunnstrom Stage IV–III gradually diverged from those of control group, but the activation coefficients remained the same after stroke, irrespective of the recovery level.
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Affiliation(s)
- Bingyu Pan
- Sensor Network and Application Research Center, School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Yingfei Sun
- Sensor Network and Application Research Center, School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Bin Xie
- Rehabilitation Department, Peking University First Hospital, Beijing, China
| | - Zhipei Huang
- Sensor Network and Application Research Center, School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Jiankang Wu
- Sensor Network and Application Research Center, School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Jiateng Hou
- Sensor Network and Application Research Center, School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Yijun Liu
- Rehabilitation Department, Peking University First Hospital, Beijing, China
| | - Zhen Huang
- Rehabilitation Department, Peking University First Hospital, Beijing, China
| | - Zhiqiang Zhang
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, United Kingdom
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Sawers A, Bhatt T. Neuromuscular determinants of slip-induced falls and recoveries in older adults. J Neurophysiol 2018; 120:1534-1546. [PMID: 29995607 DOI: 10.1152/jn.00286.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Is there a neuromuscular basis for falls? If so, it may provide new insight into falls and their assessment and treatment. We hypothesized that falls and recoveries from a laboratory-induced slip would be characterized by differences in multimuscle coordination patterns. Using muscle synergy analysis, we identified different multimuscle coordination patterns between older adults who fell and those who recovered from a laboratory-induced "feet-forward" slip. Participants who fell recruited fewer muscle synergies than participants who recovered. This suggests that a fall may result from recruitment of an inadequate number of muscle synergies to produce the necessary mechanical functions required to maintain balance. Participants who fell also recruited different muscle synergies, including one with high levels of coactivity consistent with a startle-like response. These differences in multimuscle coordination between slip outcomes were not accompanied by differences in slip difficulty or gait kinematics before or during the slip response. The differences in neuromuscular control may therefore reflect differences in sensorimotor control rather than kinematic constraints imposed by the slip, or the musculoskeletal system. Further research is required to test the robustness of these results and their interpretation with respect to additional mechanical variables (e.g., joint torques, ground reaction forces), responses to other fall types (e.g., trips), and within rather than between individuals. NEW & NOTEWORTHY Do falls and recoveries possess distinct neuromuscular features? We identified differences in neuromuscular control between older adults who fell and those who recovered from a "feet-forward" slip. Differences in neuromuscular control were not accompanied by differences in gait or slip kinematics before or during the slip response, suggesting differences in sensorimotor control rather than kinematics dictated the observed differences in neuromuscular control. An analysis of additional mechanical variables is required to confirm this interpretation.
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Affiliation(s)
- Andrew Sawers
- Department of Kinesiology, University of Illinois at Chicago , Chicago, Illinois
| | - Tanvi Bhatt
- Department of Physical Therapy, University of Illinois at Chicago , Chicago, Illinois
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35
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Tan CK, Kadone H, Watanabe H, Marushima A, Yamazaki M, Sankai Y, Suzuki K. Lateral Symmetry of Synergies in Lower Limb Muscles of Acute Post-stroke Patients After Robotic Intervention. Front Neurosci 2018; 12:276. [PMID: 29922121 PMCID: PMC5996914 DOI: 10.3389/fnins.2018.00276] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 04/09/2018] [Indexed: 01/24/2023] Open
Abstract
Gait disturbance is commonly associated with stroke, which is a serious neurological disease. With current technology, various exoskeletons have been developed to provide therapy, leading to many studies evaluating the use of such exoskeletons as an intervention tool. Although these studies report improvements in patients who had undergone robotic intervention, they are usually reported with clinical assessment, which are unable to characterize how muscle activations change in patients after robotic intervention. We believe that muscle activations can provide an objective view on gait performance of patients. To quantify improvement of lateral symmetry before and after robotic intervention, muscle synergy analysis with Non-Negative Matrix Factorization was used to evaluate patients' EMG data. Eight stroke patients in their acute phase were evaluated before and after a course of robotic intervention with the Hybrid Assistive Limb (HAL), lasting over 3 weeks. We found a significant increase in similarity between lateral synergies of patients after robotic intervention. This is associated with significant improvements in gait measures like walking speed, step cadence, stance duration percentage of gait cycle. Clinical assessments [Functional Independence Measure-Locomotion (FIM-Locomotion), FIM-Motor (General), and Fugl-Meyer Assessment-Lower Extremity (FMA-LE)] showed significant improvements as well. Our study shows that muscle synergy analysis can be a good tool to quantify the change in neuromuscular coordination of lateral symmetry during walking in stroke patients.
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Affiliation(s)
- Chun Kwang Tan
- Artificial Intelligence Laboratory, University of Tsukuba, Tsukuba, Japan
| | - Hideki Kadone
- Center for Innovative Medicine and Engineering, University of Tsukuba Hospital, Tsukuba, Japan
| | - Hiroki Watanabe
- Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Aiki Marushima
- Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Masashi Yamazaki
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Yoshiyuki Sankai
- Center for Cybernics Research, University of Tsukuba, Tsukuba, Japan.,Faculty of Engineering, University of Tsukuba, Tsukuba, Japan
| | - Kenji Suzuki
- Artificial Intelligence Laboratory, University of Tsukuba, Tsukuba, Japan.,Center for Cybernics Research, University of Tsukuba, Tsukuba, Japan.,Faculty of Engineering, University of Tsukuba, Tsukuba, Japan
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A Systematic Review on Muscle Synergies: From Building Blocks of Motor Behavior to a Neurorehabilitation Tool. Appl Bionics Biomech 2018; 2018:3615368. [PMID: 29849756 PMCID: PMC5937559 DOI: 10.1155/2018/3615368] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/29/2018] [Indexed: 12/20/2022] Open
Abstract
The central nervous system (CNS) is believed to utilize specific predefined modules, called muscle synergies (MS), to accomplish a motor task. Yet questions persist about how the CNS combines these primitives in different ways to suit the task conditions. The MS hypothesis has been a subject of debate as to whether they originate from neural origins or nonneural constraints. In this review article, we present three aspects related to the MS hypothesis: (1) the experimental and computational evidence in support of the existence of MS, (2) algorithmic approaches for extracting them from surface electromyography (EMG) signals, and (3) the possible role of MS as a neurorehabilitation tool. We note that recent advances in computational neuroscience have utilized the MS hypothesis in motor control and learning. Prospective advances in clinical, medical, and engineering sciences and in fields such as robotics and rehabilitation stand to benefit from a more thorough understanding of MS.
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37
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Challenging human locomotion: stability and modular organisation in unsteady conditions. Sci Rep 2018; 8:2740. [PMID: 29426876 PMCID: PMC5807318 DOI: 10.1038/s41598-018-21018-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 01/29/2018] [Indexed: 01/10/2023] Open
Abstract
The need to move over uneven terrain is a daily challenge. In order to face unexpected perturbations due to changes in the morphology of the terrain, the central nervous system must flexibly modify its control strategies. We analysed the local dynamic stability and the modular organisation of muscle activation (muscle synergies) during walking and running on an even- and an uneven-surface treadmill. We hypothesized a reduced stability during uneven-surface locomotion and a reorganisation of the modular control. We found a decreased stability when switching from even- to uneven-surface locomotion (p < 0.001 in walking, p = 0.001 in running). Moreover, we observed a substantial modification of the time-dependent muscle activation patterns (motor primitives) despite a general conservation of the time-independent coefficients (motor modules). The motor primitives were considerably wider in the uneven-surface condition. Specifically, the widening was significant in both the early (+40.5%, p < 0.001) and late swing (+7.7%, p = 0.040) phase in walking and in the weight acceptance (+13.6%, p = 0.006) and propulsion (+6.0%, p = 0.041) phase in running. This widening highlighted an increased motor output’s robustness (i.e. ability to cope with errors) when dealing with the unexpected perturbations. Our results confirmed the hypothesis that humans adjust their motor control strategies’ timing to deal with unsteady locomotion.
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Silva PB, Oliveira AS, Mrachacz-Kersting N, Kersting UG. Effects of wobble board training on single-leg landing neuromechanics. Scand J Med Sci Sports 2018; 28:972-982. [PMID: 29193314 DOI: 10.1111/sms.13027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2017] [Indexed: 11/29/2022]
Abstract
Balance training programs have been shown to reduce ankle sprain injuries in sports, but little is known about the transfer from this training modality to motor coordination and ankle joint biomechanics in sport-specific movements. This study aimed to investigate the effects of wobble board training on motor coordination and ankle mechanics during early single-leg landing from a lateral jump. Twenty-two healthy men were randomly assigned to either a control or a training group, who engaged in 4 weeks of wobble board training. Full-body kinematics, ground reaction force, and surface electromyography (EMG) from 12 lower limb muscles were recorded during landing. Ankle joint work in the sagittal, frontal, and transverse plane was calculated from 0 to 100 ms after landing. Non-negative matrix factorization (NMF) was applied on the concatenated EMG Pre- and Post-intervention. Wobble board training increased the ankle joint eccentric work 1.2 times in the frontal (P < .01) and 4.4 times in the transverse plane (P < .01) for trained participants. Wobble board training modified the modular organization of muscle recruitment in the early landing phase by separating the activation of plantar flexors and mediolateral ankle stabilizers. Furthermore, the activation of secondary muscles across motor modules was reduced after training, refocusing the activation on the main muscles involved in the mechanical main subfunctions for each module. These results suggest that wobble board training may modify motor coordination when landing from a lateral jump, focusing on the recruitment of specific muscles/muscle groups that optimize ankle joint stability during early ground contact in single-leg landing.
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Affiliation(s)
- P B Silva
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - A S Oliveira
- Department of Materials and Production, Aalborg University, Aalborg, Denmark
| | - N Mrachacz-Kersting
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - U G Kersting
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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Nazifi MM, Beschorner KE, Hur P. Association between Slip Severity and Muscle Synergies of Slipping. Front Hum Neurosci 2017; 11:536. [PMID: 29163111 PMCID: PMC5674011 DOI: 10.3389/fnhum.2017.00536] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 10/23/2017] [Indexed: 11/16/2022] Open
Abstract
Falls impose significant negative impacts to the US population and economy. A significant number of falls may be prevented via appropriate slip-responses since a strong relation exists between slips and falls. More importantly, as severe slips are more prone to result in a fall, identifying severe slippers along with the responsible factors for their adverse motor control and severe slipping should be the highest priority in fall prevention process. Previous studies have suggested that muscle synergies may be building blocks of the central nervous system in controlling motor tasks. Muscle synergies observed during slipping (‘post-slip-initiation synergies’ or ‘just briefly,’ ‘slipping muscle synergies’), may represent the fundamental blocks of the neural control during slipping. Hence, studying the differences in slipping muscle synergies of mild and severe slippers can potentially reveal the differences in their neural control and subsequently, indicate the responsible factors for the adverse post-slip response in severe slippers. Even though the slipping muscle synergies have been investigated before, it still remains unclear on how the slip severity is associated with the slipping muscle synergies. More importantly, muscle synergies can be interpreted not only as neural blocks but also as physical sub-tasks of the main motor task. Hence, studying the differences of slipping synergies of mild and severe slippers would reveal the discrepancies in sub-tasks of their post-slip response. These discrepancies help pinpoint the malfunctioning sub-function associated with inadequate motor response seen in severe slippers. Twenty healthy subjects were recruited and underwent an unexpected slip (to extract their slipping synergies). Subjects were classified into mild and severe slippers based on their Peak Heel Speed. An independent t-test revealed several significant inter-group differences for muscle synergies of mild and severe slippers indicating differences in their neural control of slipping. A forward dynamic simulation was utilized to reveal the functionality of each synergy. Decomposition of slipping into sub-tasks (synergies), and finding the malfunctioning sub-task in severe slippers is important as it results in a novel targeted motor-rehabilitation technique that only aims to re-establish the impaired sub-task responsible for the adverse motor-response in severe slippers.
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Affiliation(s)
- Mohammad Moein Nazifi
- Human Rehabilitation Group, Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States
| | - Kurt E Beschorner
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Industrial Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Pilwon Hur
- Human Rehabilitation Group, Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States
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Samuel OW, Li X, Geng Y, Asogbon MG, Fang P, Huang Z, Li G. Resolving the adverse impact of mobility on myoelectric pattern recognition in upper-limb multifunctional prostheses. Comput Biol Med 2017; 90:76-87. [DOI: 10.1016/j.compbiomed.2017.09.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 10/18/2022]
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